The invention relates generally to exhaust system components and in particular to a triple-baffled muffler. The art of customizing a vehicle sometimes may address the sound made by the engine while running. A broad array of various customized mufflers and other exhaust components have been created to produce desired engine sounds. It is difficult to reconcile the two goals of near silence when the engine is idling, and a loud, throaty roar when the throttle is pressed all the way to the floor.
A search of the prior art reveals various mufflers which have been developed to provide a variable level of sound from the muffler. None are closely related to the present invention, but several include features which resemble those of the present invention. Each has proven to be less than satisfactory in its own way. The present invention has been developed for the purpose of addressing and resolving these disadvantages.
Sound absorption device or muffler for blow nozzles, U.S. Pat. No. 5,036,948 (priority Jan. 12, 1989), provides a device with a bore extending from a low-pressure side of the nozzle, at which a gas flow enters the nozzle, to a high-pressure side of the nozzle, at which the gas flow streams from the nozzle through a nozzle opening formed at an end of the bore. The device includes a sound-absorbing insert for muffling noise which results from a variation in density of the gas flow as it streams through the nozzle opening and has frequencies ranging over substantially the entire audible frequency range, the sound-absorbing insert being shaped as a truncated cone and being rigidly set into the bore formed in the blow nozzle, with the smaller face of the truncated cone being disposed directly at the nozzle opening.
Silencer/muffler, U.S. Pat. No. 8,136,629 (priority Dec. 21, 2009), provides a muffler which includes an outer tube which configures an outer wall, an inner tube provided in the outer tube and having punching holes formed therein, and a sound absorbing material filled between the outer tube and the inner tube. The muffler is attached to an exhaust pipe for exhausting exhaust gas from an engine, the number of punching holes at portions of the inner tube which have a great length to the outer tube is set greater than the number of punching holes at portions of the inner tube which have a small length to the outer tube in comparison with the portions having the great length.
Variable sound muffler system, U.S. Patent App. Pub. No. US2008/0314679 (priority Aug. 5, 2005), provides a muffler system which includes a housing having two pipes perforated with holes or other shapes that slide or rotate on top of each other. The sliding or rotating pipes allow for varying degrees of alignment of the holes and thereby allow more or less sound dampening. The control of the sound dampening is actuated by an operator via an electric switch that activates at least one of the pipes inside the muffler system to rotate or slide on each other thereby aligning the holes.
Vehicle muffler and method of assembly, U.S. Pat. No. 3,638,756 (priority Dec. 30, 1969), provides a muffler which is formed of two pieces, preferably metal stampings, in which the various chambers and passages are indented or embossed. The two pieces are joined at their peripheral edges. The muffler is tuned by manually adjusting the relative size and arrangement of chambers and passages during its installation. In one modification the position of the pieces may be adjusted relative to each other to permit variable tuning.
Exhaust muffler, U.S. Pat. No. 4,161,996 (priority Jan. 21, 1977), provides a muffler intended for noise dampening of pneumatic tools, comprising a variable flow restricting passage, an attenuation chamber and a non-variable flow restricting passage in response to the actual exhaust gas pressure. A movement dampening chamber, partly defined by the valve body, communicates with the atmosphere through a restriction opening to prevent resonance vibration of the valve body.
Performance responsive muffler for internal combustion engines, U.S. Pat. No. 4,903,486 (priority Dec. 1, 1987), provides a muffler responsive to exhaust flow. The muffler includes a body having a variable restrictor located downstream from an inlet port and upstream from an outlet port of the muffler. The variable restrictor is formed with a solid wall disposed about the valving element to define a constricting annular passageway having a cross section that varies with distance from the inlet port and from the outlet port.
The prior art inventions generally require manual operation by the user and, in at least one case, cannot change the variable restriction of exhaust flow except during installation. A triple-baffled muffler, with three hinged baffles to provide increased engine sound when the throttle is pressed, would resolve these problem. The baffles open successively as a result of increased pressure from the exhaust flow, and are thus self-actuating.